Shoe press pad



Dem, 4, 1956 M. c. suERKEN 2,772,428

sHoE PRESS PAD IN V EN TOR.

WW 6 Jaw/m W #www New., L 1956 L M. C. SUERKEM SHOE PRESS PAD 3 Sheets-Sheet 2 Filed Feb. 18. 1952" INVENTOR. www JM @1M #www @www afll 4, 1956 M. c. suERKr-:N 257729428 SHOE PRESS PAD Filed Feb. 18, 1952- 3 Sheets-Shea?l 3 40 Ffa. 8 3% 1N VEN TUR.

46 5 MMC; qwkw #am y Wm SHOE PRESS PAD Maxwell C. Suerken, Erie, Pa., assigner to Lamac Process Company, Erie, Pa., a corporation of Delaware Application February 18, 1952, Serial No. 272,155

6 Claims. (Cl. 12-38) This application is a continuation in part of Patent 2,654,104, granted October 6, 1953.

Shoe presses are commonly provided with an inflatable pad for receiving a shoe which, when inflated, exerts the cementing pressure on a sole to be attached. Such pads have been in the form of leather casings with rubber bladders.

This invention is intended to improve the service life of inflatable pads by making the leather casing in the form of a tube with a longitudinal bottom seam and by making the bladder of integral molded rubber constructed so that the corners and edges are shaped and reinforced to prevent localized stress concentrations. The combination of these features results in a pad with much longer service life.

ln the drawing, Fig. 1 is a transverse section through a pad in the pressure applying position illustrating the position assumed by the pad under cementing pressure; Fig. 2 is a developed view of the leather sheet from which the cover for the pad is made; Fig. 3 is a section through an end seam of the casing; Fig. 4 is a section through a corner seam of the casing; Fig. 5 is an enlarged section through the pad in the inflated position; Fig. 6 is a similar view with the pad in deflated position; Fig. 7 is a perspective view partly broken away of a modification of the pad; Fig. 8 is a developed view of the leather sheet from which the Fig. 7 pad is made; and Figs. 9 and 10 are sections through other modicatons of the pad.

As diagrammatically indicated in Fig. l, a shoe 1 with a sole 2 to be attached is placed upon the upper surface of a pad 3 and the bladder 4 of the pad is then inflated with air pressure supplied through a stem 5. The air pressure is applied throughout the surface oi' the sole and supplies the necessary pressure for cementing. In parts of the pad where it is desirable that the pad be stitr or inflexible, reinforcements 6 are applied to the under side. These reinforcements ordinarily do not extend to the edge of the sole thus allowing the pad to conform to the shoe but preventing excessive `bulging at the sole edge thereby limiting the rolling up of the welt extension on the shoe when pressure is applied. No attempt has been made to illustrate the construction of` the press. The pad is ordinarily supported in a box frame or base 7 having side walls 8 extending up around the edges of the pad.

As shown in Fig. 2, the envelope or casing for the pad is made from a single piece 9 of llexible material, ordinarily leather, since this has proven to be the most satisfactory material for shoe cementing presses. On the under side of the leather sheet 9 are the `stilening meinbers 6 and 6a corresponding to the sections underlying the toe and heel of the shoe. Between the stiiening members 6 and 6d is an unreinforced section 10 which is free to conform to the shank of the shoe. It will be understood that the stiiening members 6 and 6a arey not always used and that the stitening members are `subject to widely varying shapes depen-ding upon the shoes to be cemented. The stitening sections 6 and 6a, iE used,

" nite States Patent O rice are on the under side so that the outer side of the casing has a smooth uninterrupted surface. In the assembled position, side aps 11 and 12 are folded inward and joined together by a central longitudinal cemented seam 13. As is common in cemented seams, the abutting surfaces are tapered so that the seam is or essentially uniform thickness. Since the seam is located at the center of the bottom section of the pad, it is subjected to substanially no stress. 1t remains ilat against the bottom of the base 7, because there is substantially no tlexing oi the casing in the region of the seam. Another advantage of the seam is that it extends longitudinally of the casing. This means that as the side flaps 11 and 12 are folded inward, the leather naturally has smoothly rounded corners such as indicated at 14, which are very close to the shape the corner sections of the casing assume under cementing pressure. From one aspect, the int`olded sides of the casing naturally result in rounded longitudinal edges of the pad, which very closely conforms to the shape the pad tends to assume under pressure. This is a substantial advantage over pad casing constructions where gussets with longitudinal stitched seams have been used. Such stitched seams are points of weakness because flexing of the sewed seam in the stiff leather wears the threads and in spite of efforts made to have the shape of the pad as manufactured correspond to the shape the pad tends to assume under pressure, there has been a troublesome problem of failure at some point along the side seams. The end construction like wise results in rounded end surfaces as well as rounded corners. As the end sections 16 at the top oi the casing are folded downward and the end sections .17, ifa at the bottom of the casing are folded upward (Fig. 3), eyelets 18 in the end sections 16 come opposite eyelets 19 in the end sections 17, 17a and the ends of the sections 16 and 17, 17a abut so as to be in position for lacing. At each of the corners (Fig. 4) there is a tab 15 which when in-folded tends to produce a curved corner inside the folded end sections. In this position, eyelets 20, 21 in the tabs 15 line up with eyelets it: and 18a so that the end tabs 1S are easily laced in position. The folding of the sections 16, 17, and 17a naturally results in rounded edges at the end sections ot the pad casing. The eyelet and laced construction is much stronger than stitching and has proven in actual practice to be trouble free.

Having greatly increased the life of the pad casing, it was perhaps inevitable that bladder failure became prominent. Efforts in the direction of applying reinforcement to the standard bladders in general use proved unsatisfactory. Almost any sort of reinforcing patch on the bladder produces a boundary point ot' stress at which failure occurs. Accordingly, the full molded construc tion illustrated in Fig. 1 was Iadopted and has proven to have a lite commensurate with the increased li of the outer casing. In the bladder construction the edge portions, both side and end, are molded essentially to conform with the shape the outer casing assumes under pressure. These edge portions are of essentially uniform thickness between points 22 and 23 which are at or slightly inward of the top and bottom corners. The portion of the ladder between the points 22 and 23 ordinarily does not llex to any great extent but remains out against the sides or" the casing at all times. Startinsy with the points 22 and 23 and working toward the center of Athe bladder there are tapered sections 24 and 25 which merge into thin flexible sections 26 and 27 which are substantially opposite the sole. Having the thin flexible sections of the bladder opposite the sole permits the bladder to follow the casing shape without stressing the side or end edge sections which is where the bladders usually tail. it is possible that the thin flexible section .'27 at the bottom may not be necessary, but the thin exible section 26 at the top is of great importance in obtaining bladders of proper ylife and necessary exibility in that area. The tapered sections 24 and 25 prevent the abrupt transition in which points of stress concentration are likely to develop. Bladder failure is a peculiar phenomenon. The bladders in general use in industry almost always fai-l at the edges and the failure starts at the inside and works out. Reinforcements added to the edges, no matter how carefully made, inevitably result in points of stress concentration at which failure can start. The failure ordinarifly starts at a point and spreads rapidly. It was not until the homogeneous full molded construction was adopted where the edges were made thick enough so as to be relatively rigid and were joined by uniformly tapered sections to the thinned-down flexible sections 26 and 27 opposite the shoe sole that acceptable bladder life was obtained. This construction increases the bladder life from ten to twenty times, which is a significant improvement when it is considered that bladders for shoe cementing press pads have been made for many years and in large quantities.

The action of the bladder and casing is illustrated in enlarged sectional views, Figs. 5 and 6, showing the pad in the inflated and deflated positions. In the deiiated position, the top wall :of the outer casing partially collapses as the air pressure is released. When the pad is inflated, there is a rolling action at the edges of the casing as the top surface bellies up around the edges of the sole. Just why the combination of a full molded bladder with thick edge sections gradually merging or tapering to thin center sections should be best accommodated to the action of the casing is not entirely clear. Such construction does, however, distinguish the bladders whose life is commensurate with the improved casing from the bladders which seem to fail quickly, because of the extraordinary life of the improved casing con-struction.

The modification of the pressure pad shown in Figs. 7 and 8 comprises an envelope or casing made from a single piece of exible material 33 containing an inflatable rubber bladder 34. The outer casing of the pad is made of leather since this has proven to be the most satisfactory material for shoe cementing presses. On the inside of the leather pad 33 are stiffening members 35 and 36 stiffening the sections of the casing underlying the toe and heel of a shoe. Between 'the stiffening members 35 and 36 is an unreinforced section 37 which is free to conform to the shank of the shoe. At the side edges of the pad are side edge stiffening members 38 opposite the toe stiiening section 3S and side edge stiffening members 39 opposite the heel stiffening member 36. The stiffening sections 33 and 39 are also on the inner side of the leather sheet 33. In the assembled position side tiaps 40 of the sheet 33 are folded inward and joined together by a cemented central longitudinal seam 4l. The seam 41 being at the center of the bottom section of the leather pad casing is subjected to substantially no stress. lt remains flat against the bottom of the base 7 and because there is substantially no flexing is an exceedingly durable and permanent seam. This results in a leather casing for the pad having relatively rigid sections formed by the stiffening members 35 and 38 opposite the toe of the shoe, corresponding relatively rigid sections formed by the stiffening members 36 and 39 opposite the heel of the shoe, and a flexible section 37 in the region corresponding to the shank of the shoe. This flexible sect-ion is particularly desirable since it permits a uniform cementing pressure throughout the entire sole area. At the toe end of the pad casing the end section 42 is joined around its periphery to the edges 43 by stitching. The toe ysection of the pad is ordinarily protected against bursting stresses by a cover plate (not shown). Also, the toe section is subject to relatively little iiexing and it is the flexing which is particularly injurious to stitched seams. The heel end of the pad casing is provided with lacing receiving eyelets 45. The heel setltion is likewise subject to little flexing and the lacing provides an essentially permanent connection. The lacing also provides an easy way of replacing the bladder 34. There -is a stitched section 46 at the corners of the heel section of the pad. This stitched section is located in a region subject to little flexing and the stitching accordingly has the desired durability. The elimination :of stitched seams in the flexible region 37 of the pad not only increases the life of the pad but it also permits better accommodation of the flexible section to the arch of the shoe thereby securing a more uniform cementing pressure. Both of these advantages are important.

In Figs. 9 and l() are shown modifications of the pad which have the envelope folded about the longitudinal axis of the pad. In Fig. 9, a single piece of leather is used to provide both the envelope and the stiffening section opposite the heel and toe. At either the heel or toe sections, the envelope has a double thickness at the top and side sections and a single thickness at the bottom section. This is accomplished by having one edge of the top section 77 depend at one side to provide a side section 78 and by having the bottom section 79 which is integral with the other side section 80, extend along the inner surface of the side sections 78 and 80 and of the top section 77. This results in a double thickness of leather at the top and side sections which provides the desirable stiifening. The double thickness sections are cemented together thereby providing a permanent connection in which the entire top and side of the pad comprise a longitudinal seam in which a substantial part is in a region subjected to limited fiexing under cementing pressure. In the region between the heel and toe where greater flexibility of the pad is required, the bottom section 79 is terminated at the edge between 77 and 78 so that there is only a single thickness of leather in the top section 77 and preferably only a single thickness of leather in the upper portions of the side sections 78 and 80. At the cut away portion of the bottom section there need be only suicient overlap to provide a cemented seam of the required strength. The end closure for Fig. 9 may be in accordance with the previously described constructions.

In Fig. l0, the pad is made from the leather sheet 33 shown in Figs.. 7 and 8. However, instead of separate stiffening members 35, 36, 38, 39, the stiffening of the heel and toe sections of the pad is effected by U-shaped pieces of leather having center sections 81 and depending side sections 82 which are cemented to the under or inner surface of the pad.

What is claimed as new is:

l. A shoe press pad comprising a fiattened tubular casing having its longitudinal axis extending lengthwise of a shoe to be pressed, said casing having top, side, and bottom sections formed of an integral sheet of flexible material having its side edges rolled inward and joined together by a longitudinal seam in the bottom section of the casing.

2. A shoe press pad comprising a attened tubular casing having its longitudinal axis extending lengthwise of a shoe to be pressed, said casing being made of leather or like sheet material having its top, sides, and infolded sections at the bottom of the sides all formed from an integral seamless sheet, a longitudinal cemented seam joining the infolded sections, a fluid pressure bag within the casing, stiffening sections on the underside of top sections of the sheet at positions corresponding to the heel and toe of a shoe resting on the pad.

3. A shoe press pad comprising a flattened tubular easing having its longitudinal axis extending lengthwise of a shoe to be pressed, said casing having top, side, and bottom sections formed of a sheet of flexible material having its side edges folded inward and cemented together by a central longitudinal seam in the bottom section of the casing, and a fluid pressure bag within the casing.

4, A shoe press pad casing comprising an elongated flattened tubular envelope formed of an integral seamless sheet with the sides infolded and joined by a longitudinal cemented seam at the bottom, top and bottom flaps at one end of the sheet folded toward each other and forming a smooth end wall with edges abutting and presented to each other and laced together, and corner flaps at the sides infolded beneath and laced to the top and bottom ilaps.

5. A shoe press pad comprising a llattened tubular casing having its longitudinal axis extending lengthwise of a shoe to be pressed, said casing having top, side, and bottom sections formed of a sheet of exible material having its side edges folded inward and cemented together by a central longitudinal seam in the bottom section of the casing, and a fluid pressure bag within the casing, comprising an integral homogeneous rubber envelope molded to conform generally with the shape of the pad, said envelope having thick edge sections at the sides and sides and ends curved inward at top and bottom and top and bottom sections bridging the space between the upper and lower edges of the edge sections, the top and bottom sections being thick at the junctions with the edge sections and at least the top section gradually tapering down in thickness inward from the edge sections and merging into thin central llexing sections underlying the region occupied by a shoe to be pressed.

6. A shoe press pad comprising a attened tubular casing having its longitudinal axis extending lengthwise of a.

shoe to be pressed, said casing having top, side, and bottom sections formed of a sheet of iiexible material having its side edges folded inward and cemented together by a central longitudinal seam in the bottom section of the casing, and a fluid pressure bag within the casing, comprising an integral homogeneous rubber envelope molded to conform generally with the shape of the pad, said envelope having thickened edge sections and top and bottom sections bridging the space between the upper and lower edges of the edge sections, the top section being thick` at the junctions with the edge sections and gradually tapering down in thickness inward from the edge sections and merging into a thin central flexing section underlying the region occupied by a shoe to be pressed.

References Cited in the file of this patent UNITED STATES PATENTS 1,754,056 Shulebarger Apr. 8, 1930 1,789,599 Ruhr et al. Jan. 20, 1931 2,022,501 Cramer Nov. 26, 1935 2,076,696 Brauner Apr. 13, 1937 2,095,658 Card, Jr Oct. 12, 1937 2,143,101 Best et al Jan. 10, 1939 FOREIGN PATENTS 446,152 Germany June 25, 1927 584,419 Great Britain Jan.. 14, 1947 

